JAXB 解组错误：预期元素为 { } Root

JAXB 解组错误：预期元素为 <{ } Root>

java
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement(name = "Book")
public class Book {
    private String title;
    private String author;
    public String getTitle() {
        return title;
    }
    @XmlElement
    public void setTitle(String title) {
        this.title = title;
    }
    public String getAuthor() {
        return author;
    }
    @XmlElement
    public void setAuthor(String author) {
        this.author = author;
    }
}

java
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.File;
public class JAXBExample {
    public static void main(String[] args) {
        try {
            // 创建JAXBContext对象
            JAXBContext jaxbContext = JAXBContext.newInstance(Book.class);
            // 创建Marshaller对象
            Marshaller marshaller = jaxbContext.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            // 创建Book对象
            Book book = new Book();
            book.setTitle("Java Programming");
            book.setAuthor("John Smith");
            // 将Book对象保存到XML文件中
            marshaller.marshal(book, new File("book.xml"));
            // 创建Unmarshaller对象
            Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
            // 从XML文件中解组Book对象
            Book unmarshalledBook = (Book) unmarshaller.unmarshal(new File("book.xml"));
            // 打印解组后的Book对象信息
            System.out.println("Title: " + unmarshalledBook.getTitle());
            System.out.println("Author: " + unmarshalledBook.getAuthor());
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}